Realy good to look at Dave, thanks for posting.
As Peter has said thanks for the single sub as well as I'm running a similar setup as you but with a Penatx K5 SLR.
Some of my work on the same Galaxy looks sad in comparison and I can see why looking at yours.
I had only been doing 210 sec subs at iso 800 and with only 30 minutes worth the other night before it got too hazy my 30 minutes of subs look like your single sub.
I think my next series will be at least 5 min subs and I'll see how I go from there.
Cheers